Apparatus for inducing respiration



M 11, 1945: H. E. ENSLIN ETAL 2,333,131-

' APPARATUS FOR INDUCING RESPIRATION F i led Jan. -29, 1945 2Sheets-Sheet 1 //v VE/V 727E251 HERBERT E. E/YSLl/V saengvyc. 234M205 ATTOfP/YE vs H. E. ENSLIN ETAL 2,383,181

APPARATUS FOR INDUGING RESPIRATION Filed Jan. 29, 1945 2 Sheets-Sheet 2M Wwm W E WW O F T R m E5 glZ' A &

sm mm w 7 R m Patented Aug. 21, 1945 e 2,383,181 a APPARATUS FORINDUCING RESPIBATION Herbert E. Ensun, Beverly,

Mass and Edgren C.

Wallace, Miami, Fla., assignorsto Revair Cor-- poration, Boston, Mass.,

chusetts a corporatiori'of Massa- Applicatio n Janua ryi29, 1943, SerialNo. ii4, 020

4 Gianna, (01. 128-29 This invention relates toapparatus foradministering oxygen-containing.orother gases to the lungs forthepurposeof restoring normal respiration; and pertains more particularly toimprovements in portable, manually-operated, me-

chanical respirators intended to be used in lieu of or as an adjunct towell known methods of manual resuscitation.

The principal purpose of the, invention is to.

provide a safe, efficient and relatively sirnpledevice which may bereadily transported and easily operated by a laymamwhich will supply, tothe lungs either fresh air, pure oxygenor gaseous mixtures, undercontrollableconditions of volume and pressure, and which will withdrawrelatively smaller proportions ofexpendedgases until the lungs areadequately inflated and natural breathing has been induced! we are awarethat ,various types oipulrnotors, mechanical resuscitators and otherrespirating devices have heretoforebeen devised, but itiis commonlyknown that such devices have m'etwith the disapproval of the ,medicalprofession for general usage because they could not be regulated orcontrolled toQin'duce' pulmonary ventilation under conditions; of, time,volumdand pressure approximating natural, respiration of the individualbeing treated. It has been found that these prior devices creatabnorrnalconditions and Ea ie ratory tract {by overdistention funder excessivepositive pressures on forced inspiration, and by harmful contraction.under I excessive negative pressureson forced expiration. A furtherobjecb the ,pressure-and-suction type of appara I tus has been theinability of such devices to afford anadequate exchange of gases becauseof the too raprd constriction of the alevoli and bronchia.

Itis riowfecdgnizedthat. resuscitation after asphixia orfthe restorationof natural respiration after failure for other causes is primarilyachemlcal, aetion involving a renewed supply of oxygen which stimulatescirculation, improves the tonus and elasticity of the, diaphragm andthoracic muscles and inducesmormal pulmonary ventilation, Hence,satisfactory results maysafely be achieved by, administeringoxygen-containing gases to the lungs under natural conditions of time,volume and pressure, without employing the excessive quantitiesandpressureswhioh were considered necessary to accomplishthe resultsmechanical phenomena, is understood, nevertheless, that the" gasesadministered to the lungs are absorbed or diffused through the tissues;

injure the tissues of the lungs and respiaccording to the mechanicalprinciples applying to inflated bodies having capacities and surfacetensions comparable to the lungs. s 5 i i The improved apparatus whichwe 'have devised has been designed after extended research.- or thephysiological conditions affecting artificial respiration and themechanical requirements necessary to satisfy those conditions; and.itriS the main object of this invention to obviatethe objectionablefeatures and harmful effectsof the prior devices, and to provide meansfor so-ade justing and controlling'theoperation of our inachine that itsrate or operation, and the volume and pressure of gases delivered to orwithdrawn from the lungs, will approach as nearly as practica-ble to theindividual physiologic conditions of natural breathing-even when the:machine manipulated by an inexperienced operator.

Thisobjective is attained loy equipping the improved machne withcontrols which ensure gradual inflation of thelungs with fresh airsupplied in safe quantitiesat harmless pressuresand in"- itiallywithdrawn in substantially smaller quantities at lower pressures,creasing minimal supply remains in the lungs; and which permitexpirations of larger amounts atilhigher pressures after the lungs havebeen filled to such an extent that muscular reflex expels theexhaustedair. Thus, normal respiration is induced and maintained while themachine is being operated and without further ad'- justment of itscontrols. 1

These and other salutary features of the improved apparatus will becomeapparent from the .following description of theconstruction andoperationoi the recommended embodiment of the invention shown in theaccompanying drawings, in which: A

I Fig. 1 is a perspectiveview of our apparatus, with a portionofthecontrol compartment broken w y; 3 H r Fig. 2 is a vertical section ofthe machine taken on lineII of Fig. 3, with certain partsjin ele'vation;

Fig. 3 is a horizontal section on-line ill-111 Figs. 4 to 9 inclusiveare detail section. views taken onlines IV, V, spectively, of Fig, 3; y

Fig.10 is'a developed view in perspective of the parts of the bearingand loclrmechanisrn at vr, v11, vnr and ixg e the top of the centralcylinder in Fig. 2;

adjustable valve mechanism at the bottom central cylinder of Fig. 2; and

detail of an of the Fig; 11 is an enlarged sectional so that a graduallyin-- Fig. 12 is a perspective view to larger scale of an air-filtershown in Fig. 7.

In the particular embodiment chosen for the purpose of illustration, theimproved mechanical respirator is of the hand-operated pump type,comprising in general a pressure cylinder, a suction cylinder, anintermediate cushion cylinder acting as-a pneumatic brake forcontrolling. the speed of reciprocation of the pistons moving in saidcylinders; an operating handle connected to the three pistons; aremounted, having ports and check'valves regulating the admission anddischarge of air or oxygen-containing gases to andfrom the cylinders; anadjustable valve for controlling the rate ofreciprocation of the pistonin the brake cylinder; manual valves controlling the supply of pure air,oxygen or mixtures thereof, to the zles associated suction cylinders, towhich tubes leading to a suitable face mask may be attached, thetwonozzles having openings substantially different indiameter for apurpose hereafter explained; and. a control chamber having ventsdisposed in the conduit between the respective nozzlesand thecorresponding cylinders, and manually controlled valves simultaneouslyoperable to open or close the vent openings and thereby regulate boththe volume and pressureof the gas delivered. to the lungs or withdrawntherefromv by' the; operation of the machine.

The base 2| of the machine may be a. metal casting providing a bridgedopening for receiving the operators foot which bears upon a bottom plate22. be made of-metal, preferably plated on the inside to avoidcorrosion, or of other suitable material. The} are suitably mounted inpright position on the base 21, and the lower portions of. the cylinderare preferably shielded and reinforced by a casing 26 of plastic or thelike. The control chamber 2'! is mounted on thebaseagainstv the shield25.

In the aligned arrangement shown, 23 is the pressure or inspiratingcylinder, 25 is the suction or expirating cylinder, and 24- is. thebrakeor stroke control cylinder; but it will be understood that. thecylinders may be disposedin other formations if. desired. Eachcylinderhas a suitable piston and rod as shown in. Fig. 2, thepistonshaving suitable compression; rings, the rods being tubular and havingvent openingstopermit free circulation of ai-ra-bove the pistonsasindicated in said figure; and each of the operating cylinders has acapor head afiordinga bearingforits piston rod. The brake cylinder 24has a packer head providing a releasablelock for the operating handle ashereafter described.

The upper ends of the piston rods are connected to a handle 28 forreciprocating the three. pistons simultaneously, and the bottom portionof the handle is provided with a bridge-like latch member 29 havingflanged legs 30 -(Fig..10.) releasably engaged by the inturned lugs 3|of a locking ring 32, to hold the handle andpiston rods in downward orclosed position when the apparatus is not, in use (Fig. 2). As bestindicated in Fig. 10, the locking ring turns about the-threadedstem of apacker head 33 which screws into the top of cylinder 24 a nut 34' holdsthe-ringv against -displacement whilepermitting itsrotation by hand; anda tapered bushing, 34 and packer head nut 35 threading on the packerhead 33 .to provide a relatively tight bearing for the piston rod ot thestroke control cylinder. Downward movement of i a base on which thecylinders machine; nozwith the respective pressure and The threecylinders-.23, 24 and 25 may thereto by a lock nut 37.

the handle is limited by its engagement with the hubs of the caps oncylinders 23 and 25 (Fig. 2).

The base of the stroke control cylinder 24 is fitted with an internalnut 36 (Figs. 2 and 11) having adepending end projecting through the topportion of the base member 2| and secured Said nut end and lockingmember have vent openings 38and 39, respectively; and an orific'ed.screw 40having a valve tip 4| threads in the upper end of the nut 36 toopen or close the opening 38 and thereby regulate the flow of airthrough the screw orifice 42 and beneath the brake piston.4'3. In Figs.2

' and 11 the adjustable valve is closed, but it will be matic cushionwhich obvious manner 5| and.52. v p pure air, and is provided with. afilter. comprising understood that the screw 40 may be turned to openthe port 38 to such extent as may be desired.

It will also be evident that the adjusting valve must beregulated-before the piston 43 is placed in. the cylinder 24, so thatthe adjustment cannot'be changed without dismantling the ma chine.Hence, the machine may be tested and regulated at the factory until thebrake cylinder performs its desired function of affording a pneupreventsabrupt operation of the handle 28'and tendsto control the spcedofreciprocation to the desired rate of about six-- teen to twenty strokesper minute. If desired, a check valve (not shown) may be employed inanto close theorif ce 42 in the-upstroke of piston 43.

The admission, of pure air, oxygen: or other gases, or mixtures thereof,to the pressure cylinder 23. is regulated by a. pair ofv valved inletports Port 5| (Fig. 7') isintended to supply an apertured tube 53.containing a. sleeve 54 0ffelt or other suitable air-filtering.material; and a spring 55 for retaining thefelt sleeve mpropfe'r'position within the tube. The-valve or. took of this port is regulated.by ,a knob. 45v (Fig. 3) which may have suitable indicationsto designateits setting. W p

Gas-intake ,port..52 (Fig-5) has a hose connector 56 for the attachmentof a tube. 51 leading from a tank'containing oxygen or. QthergaSes to beadministered to the lungsjiand-aknob ,58 for regulating the valveopening. -It will be understood that either port may be used,separately, or that both ports may be simultaneously employed to supplyany oxygen (or other gases); and it will. also be ap-T parent that thevalves of both ports. may be controlled by a single regulating knob, ifdesired. I These intake ports communicate with cylinder 23 through ducts59 and 60, respectivelmjthe openings in the base of. the cylinder' beingequipp d with ball check valves BI and62, re-, spectively, whichpermitthesgases to enter 'the cylinder on the upstroke of pressure piston 63but seat on the downstroke thereof. Thegdischarge port 64 of thepressure. cylinder (Fig. .8) communicates through duct 65 and ball'check valve 66 with a pressure (regulator chamber 61 located in thecontrol chamber 21; said regulator having a small vent opening 68 (Fig.4) controlled by a needle valve or plunger 69, and a larger outlet portcommunicating through a nipple 10: with a nozzle H to which a tube of 1the face mask may be fitte A safety valve 12 is located in the duct:between the regulator 61 and: the hose connector H, the ball valve 12being of such weight that it will open under pressures exceeding 25 mm.(Hg) above atmosphere, at the lung. A Whistle signal 13 is located abovethis. escape valve so desired mixture of air land that the operator iswarned when the pressure exceeds the maximum valve for safe operation ofthe machine. i

The base' of suction cylinder 25 (Fig; 6) has an inlet port I equippedwith ball check valve 16 and communicating through duct 11 with asuctionl regulator chamber 18 located in the control chamber. .Thisregulator has a vent opening 19 regulated by a plunger or needle valve'80: (Fig. 4), and an intake nipple 8| I equipped with a hose connector82 to whichthe port expels air (and also any water or mucous which maybe drawn into cylinder on the downstroke of the suction piston 86 (Fig.2), when thevalve 84 is opened by pressure of the exhausted gas withinthe cylinder-25.

The needle valves 69 and 80 (Fig. 4) in the control chamber, aresimultaneously actuated in the same direction and to the same degree, bya cam 9| which bears against a plunger. bar 92 attached to both valveplungers. Thecam shaft 93 is rotated. by a regulating knob 94 locatedoutside the chamber 21 (Figs. 1 and 3), and the bar .92 is held againstthe cam'by a spring 95 connected thereto through a yoke 96, and attachedat its other end to the top portion of the base memberZl (Fig. 4).erably has four rises as'indicated in Fig. 4, giving four adjustablepositions of the pressure control valves, and these positions may beindicated on the pressure control knob adjuster 94.

Adjustment of these control valves 69 and 80 enables the user of theapparatus to control both volume and pressure of the gases delivered bythe positive pressure cylinder 23 or exhausted by the negative pressurecylinder 25,'by venting to atmosphere a predetermined proportion of theair or gas passing to the lungs through outlet nozzle II or withdrawnfrom the lung through intake nozzle 32. Such adjustment is necessary tosupply the correct volume and pressure for the lung capacity of thepatient as determined by his age or physical condition, and theadcontrol valves, or endeavor to remove any such obstructions." Hence,the three controls upon excessive pressure supplement each' other andcooperate in ensuring that the respirator may be efficiently operated atnormal speed without injury to the patient due to excessive pressures.

-It will be noted 1 that the adjustable control valves 69 and 80 operatesimultaneously to re- .duce both volume andpressure on the expiratingstroke as well as on the inspirating stroke of the respirator..' For thereasons previously explained, it is very importantthat the negativepressure created by the suction cylinder 25 be reduced proportionatelyto anyreduction of positive 23, so that the pressure down stroke incylinder differential between the positive and negative sides of the.apparatus be maintained particularlyduring the early stages pressurecreated by the -of operation.

The cam 9| prefjustment may obviously be made during operation of theapparatus as well as in advance,

merely by turning the regulating knob 94. The machine and its controlsare preferably so constructed and adjusted that the maximum volume ofair or gas delivered by the pressure cylinder (with the valve 69 closed)is approximately 500 cc. at a pressure in the vicinity of 25 to 30 mm.(Hg) above atmosphere, at the lungs; and that the minimum volume isapproximately 109 cc. at a pressure of about 5 mm. at the lung.Intermediate conditions will depend upon the setting of the regulatingknob.

It will be understood that this volume-pressure control operatesindependently of the stroke control and of the safety valve, but it willbe appreciated that excessive positive pressures, caused either by toospeedy operation of themachine or by obstructions in the throat, larynxor trachae, will immediately be relieved by the safety valve and thewhistle signal will warn the operator to reduce his speed, regulate theSuch pressure differential (and. complemental volume differential) isinfluenced by the relative sizes of the openings 9! and 98 in the hosecon nectors B2 and 1|,respectively, by the provisions of expansionchambers in the regulators 'ls and 61 (Fig. 4), and by the drop inpressure withinthelungs and tubes of the patient when a collapsed lungis gradually filled on successive in spirating strokes of the machine.It will be apparentfrom Fig. 4 that the opening in the connector 82 is.substantially smaller than that in connector", preferably in theproportion of one to four in cross-sectional area. The differentialcaused by the relative size of the openings 91 and l flis, however,overcome after the lungs have been completely expanded, so that themuscular contraction of the diaphragm will thereafter ex pel a. volumeof air substantially equal to that delivered by the apparatus, atsubstantially the same pressure. .Thus normal breathing is .in-

duced and. maintained even though the patient is still unconscious. Thiscondition will normally be reached after thirty to forty strokes of themachine, and thereafter normal tidal exchange of fresh air is uniformlymaintained until the patient recovers.

It will be appreciated that optimum results of the use of theimproved'respirator will depend upon the size of the ducts or conduitsbetween the respective operating cylinders and their hose connectorsandupon the weight of the balls or other valve elements in the safetyvalves and the check valves, particularly ball valves 12 and 1B. Theformer should release, as aforesaid, under positive pressure of about 25to 30 mm. (Hg) above atmosphere, and the latter should unseat at anegative pressure of approximately 6 to 8 mm. Thus, when the pressurecylinder initially delivers about 500 cc. of fresh air (or other gases)to the lungs at 25 mm. pressure, the first/upstroke of the piston willwithdraw approximately 125 cc. of exhausted air from the lungs at anegative pressure of about 7 mm. Under succeeding inspirating strokesthe volume of residual air in the lungs is gradually increased and thequantity withdrawn is also progressively increased under successiveexpirating strokes, until a normal tidal exchange of the average volumeof 500 cc. is induced as aforesaid.

Such gradual filling up of the lungs, coupled with the safety factoralforded by the relief valve 12, the limitation on the speed ofoperation and the adjustment permitted b the pressure control eventhough the respirator is operated by an ineicperiencedtperson. Thedeviceaherein;described may bez manufactureds at reasonable cost; it issmall; compact, and-portable; it is easy to operate emciently: under"simple; instructions which; may benpaclced- Wi'thathesv machine; andaitmay beused confid'ently ands-safelyin any: cases of" asphixia',d'llH'ibOiDGfSDIIQUSi gases; electric. shock; water submersiomortheflikap a Wevciaimaz? 1-. In; respirating: apparatus of: thecharacter described: having: a pressure cylinder, a suction cylindenandrzoutlet andzintake ducts leading from thG-LIESDEQHVET cylinders to:inspirating and expinatin'g li'ose'connectors; pressure control meanscomprising movable-r valves operatively disposed im the respective:ducts; said ducts having: vent openings-z. controlled by said: valvesrtopermit; the escape of air' therefronr when; the valves" are opened, abar interconnecting said valves; a cam engaging said bar; andmanually-operable'means for-rotating said camx to simultaneouslyregulate both valves; r

v2. In" respiratingapparatus of the character described having a:pressure cylinder; a suction cylinder and outlet and intakeoucts leadingfrom the respective cylinders 'toinspirating and expirating: hose"connectors; a stroke control cy1.-'

indervhaving' an apertured valve member-in: its base, and avalve-closin'gZ-screw threading downwardly-v into said. member; wherebythe valve opening may-be= regulated by turning: said screwonly-"Whenrthe cylinder is open; each: oftthe' three having pistons andpiston: rods; and

cylinders the three; rods being; connected to an operating handle; sothat the rateof movement of" the pistonst inythe pressure andsuctioncylinders is governed 'bythe rate of movement of thepiston'in thecontrol cylinder.

3. In respirating apparatus of the character described having. apressure cylinder, a' suction cylinder; and; outlet andrintake ductsleading from the: respective; cylinderstoinspirating: and; expiratinghose connectors, a controkchamber: dis-,- posed adjacent! the: bases ofsaid cylinders-and containing aportionaof each; of said ducts,:.saidducts having; vent:- openings; disposed within said chamber, andvpressure control means: comprising movable valves operatively disposed:in the; re:- spectiveducts. and regulating; the. escape-of: air throughthe; respective vent openings; alinkdnxterconnecting said.valves;. and avalve actuator engaging-:- said link,-. through; the compartmentwalland. having an operable-handle accessible outside the" compartmennpwhereby bothi valves are simultaneously regulated in\ unison by turningthe handle;

45.. In: respirating: apparatus of the character described: having. a:pressure cylinder;. a: suction cylinder andoutlet andaintake ductsleading-"from the respective cylinders to inspirating' and: expirating;hose: connectors," a control chamber disposedadjacent thebases: of.said" cylinders and containing axporti'on of each of said ducts,-saidductsshaving vent openings disposed within said chamber; andzpressure:control means comprising movable valves 'operativelyv: disposed; invtherespective ducts and regulating the escape of" air through therespective ventiopenin'gs; a link in:- terconnecting said valves,vai'sprin'g connectedirt'o thelink-and-stendingto: move: the valves tovent closing position, a: cam engaging said link. for opening thevalvesgpandi a rod extending through the: compartment. wall and havinga, knob accessibleoutside the.- compartment, whereby both valves: aresimultaneously regulated in' unison by turning theknob.

HERBERT ENSLIN. EDG-REN' o; WALL CE:

said: actuator extending

